The carbapenems are a class of broad-spectrum beta-lactam antibacterials with activity against many gram-positive and gram-negative bacteria and anaerobes. They penetrate cell walls and bind to penicillin-binding protein (PBP) targets.
Imipenem has the greatest affinity for PBP 1A, 1B, and 2, and its lethal effect is related to binding to PBP 2 and 1B. This antibiotic is active against a wide range of gram-positive and gram-negative organisms and is stable in the presence of beta-lactamases.
Ertapenem has a particular affinity for PBPs 2 and 3. This agent is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, cephalosporinases and extended-spectrum beta-lactamases.
The carbapenems are ineffective against MRSA or Enterococcus faecium.
They commonly cause mild transient aminotransferase elevations and can rarely result in clinically apparent, cholestatic liver injury.